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TVR M Series
The TVR M Series is a series of sports cars built by automaker TVR between 1972 and 1979. The series replaced the outgoing TVR Vixen and Tuscan models, and is characterized by a common chassis and shared body style. As with other TVR models before and since, the M Series cars used a front mid-engine, rear-wheel drive layout and body-on-frame construction. The bodies themselves were built from glass-reinforced plastic (GRP). The era of the M Series is commonly associated with Martin Lilley, who, together with his father, took ownership of the company on November 30, 1965. The M Series was regarded by contemporary reviewers as being loud and fast, and having excellent roadholding. This came at the expense of unusual ergonomics, and heating and ventilation systems that were sometimes problematic. The series includes the 1600M, 2500M, 3000M, 3000S, and Taimar, as well as turbocharged versions of the 3000M, 3000S, and Taimar. A small number of 5.0L Ford V8-powered cars were finished or converted by the TVR North America importer; these were sold as the 5000M. A total of 2,465 M Series cars were built over the nine years of production. Because of the hand-built and low-volume nature of TVR production, there are many small and often-undocumented variations between cars of the same model that arise due to component availability and minor changes in the build process. Chassis The backbone chassis for the M Series cars was designed by automotive engineer and dealer Mike Bigland in 1971. Bigland had been hired by Lilley after demonstrating a number of suspension and steering improvements he had made to a 1967 TVR Tuscan SE owned by one John Burton. The chassis Bigland designed was of a central-backbone layout with perimeter tubes. Both round- and square-section 14-gauge and 16-gauge steel tube was used in the construction, with the square sections used to allow easier joining of the frame to the body. To facilitate production of the new chassis, Lilley upgraded TVR's workshop with fixtures that allowed two welders to produce five units per week. Unusual at the time, TVR offered a five-year guarantee against corrosion on the M Series chassis. Corrosion was prevented by leaving a film of oil from the manufacturing process on the metal, capping the ends of the tubes, and fastening components without driving fasteners through the tube walls. The radiator selected for the M Series was shallow enough to allow locating the spare wheel in front of the engine; this improved luggage space behind the seats (where the spare wheel had been stored on pre-M-Series models) and also offered some additional crash protection for occupants. An M Series car was sent to the Motor Industry Research Association in 1971 for crash testing, and it was the only vehicle that remained steerable after a 30 mph (48 km/h) front-end collision with a concrete wall. The car's suspension was via double wishbones and coil springs front and rear. Although the wishbones and aluminum hub carriers were an original TVR design, many components on the cars were sourced from other manufacturers (such as the Triumph TR6 brake assemblies). Steering on all cars was via rack-and-pinion. Because of production overlap between the M Series cars and earlier models, some earlier models were built with the pre-M bodywork over an M Series chassis. This includes the last series of the TVR 2500 (comprising ninety-six cars; not to be confused with the 2500M), all twenty-three Vixen S4s, and the final six TVR 1300s (which used the Triumph Spitfire 1296 cc engine) Body and trim The M Series body was an evolution of the outgoing Vixen/Tuscan body. The doors, roof, forward bulkhead, and front windscreen were kept the same, leaving the bonnet and rear end to be restyled. At the start of M Series production, the fiberglass sections were baked at 140 °F (60 °C) after being moulded, then given an etch coat, six coats of primer, and three coats of nitrocellulose lacquer paint. Partway through M Series production, the paint shop changed to a two-pack acrylic paint process. Bigland styled the car's bonnet while Lilley styled the rear with the help of Joe Mleczek, who had been with the company since 1959 and who had experience in working GRP. Lilley also designed the interior and trim. Initially, all three of the 1600M, 2500M, and 3000M featured vents on the bonnet and front wings. By 1975, the 1600M and 3000M were being built without the vents but they were retained on the 2500M due to its tendency to run hot. Many components were sourced from Ford models, including the Consul windscreen that was used on all M Series variants apart from the 3000S. Multiple styles of alloy wheels were offered on the cars over the course of production, including a design by Wolfrace and TVR's own "T-slot". Chrome-plated steel bumpers, adapted from those used on the Triumph 2000, were used until around 1976, at which point they were replaced with black foam rubber bumpers. The corduroy-covered seats used in the M Series were finished by Callow & Maddox Ltd., a car trimming and upholstering company then located in Exhall, Coventry. The foam padding used in the seats has a tendency to crumble and disintegrate, which prompts some owners to find suitable replacement seats. Most aftermarket seats will not fit in the glassfiber tub; only unusually low and narrow seats (such as those from the 1984-1988 Pontiac Fiero) can accommodate the car's bodyshell. During M Series production, TVR was dealing with more than two hundred external suppliers, and stored approximately three months' worth of components to reduce sensitivity to outside production variation. After production of the M Series ended, TVR sold the production rights and tooling for many M Series components (including GRP bodies) to David Gerald TVR Sportscars Ltd. 1600M The 1600M, introduced in 1972, used the 1.6L Ford Kent engine as found in the Ford Capri GT. The 1600M was discontinued in 1973, only to be revived for the 1975 model year to meet increased demand for fuel-efficient vehicles in the wake of the 1973 oil crisis. In October 1972, it cost £1980. A total of 148 were built by the time production finally ended in 1977. Specifications *Top speed - 105 mph (169 km/h) *Acceleration: :0-60 mph: 10.4 sec :30-50 mph in top: 10.4 sec :50-70 mph in top: 9.5 sec *Engine displacement - 1588cc (bore and stroke: 81 mm (3.2 in) x 77.6 mm (3.1 in)) *Engine type - Normally aspirated inline-four *Compression ratio - 9.0:1 *Fueling - Twin-choke Weber carburetor *Peak power - 86 bhp (64 kW; 87 PS) @ 5500 rpm *Peak torque - 92 lb·ft (125 N·m) @ 4000 rpm *Transmission - 4-speed *Number built - 148 *Chassis numbers: :2288FM through 2623FM (1972-73) :3384FM through 3938FM (1975-77) 2500M As the United States was always an important market for TVR, the 2500M used the 2.5L straight-six engine from the Triumph TR6 due to that engine being ready for US emissions certification. Also borrowed from the TR6 were its gearbox, differential, and front suspension uprights. The 2500M was only offered in the UK home market until 1973, after which point it was no longer sold there due to the availability of the 3000M, which featured significantly better performance. Later, with the introduction of the TR7, Triumph stopped production of the 2.5L TR6 engine, and TVR discontinued the 2500M completely when supplies of the engine were exhausted in 1977. In October 1972, the 2500M cost £2151. Between 1972 and 1977, 947 2500Ms were sold. Specifications *Top speed - 109 mph (175 km/h) *Acceleration - 0-60 mph: 9.3 sec *Engine displacement - 2498cc (bore and stroke: 74.7 mm (2.9 in) x 95 mm (3.7 in)) *Engine type - Normally aspirated straight six *Compression ratio - 8.5:1 *Fueling - Twin Zenith Carburetters *Peak power - 106 bhp (79 kW; 107 PS) @ 4900 rpm *Peak torque - 133 lb·ft (180 N·m) @ 3000 rpm *Transmission - 4-speed *Number built - 947 *Chassis numbers: :2090T (prototype) :2240TM through 4094TM 3000M, Taimar, and 3000S As a higher-performance alternative to the 1600M and 2500M, TVR offered the 3000M, which used the 3.0L Ford Essex V6 and cost £2278 in October 1972. Produced for only one year between 1973 and 1974, the 3000ML was a special luxury version of the 3000M that included a wooden fascia, leather trim, Wilton carpets, sunroof, and high-backed seats of a style different than that found in the standard cars. A total of 654 naturally aspirated 3000Ms were built. The first major alteration to the M Series body was the hatchback Taimar, introduced at the October 1976 London Motor Show and using the same mechanicals as the 3000M. The name was supposedly created from "Tailgate Martin". The opening hatchback alleviated the previous difficulty of maneuvering luggage over the seats to stow it in the cargo area, and the hatch itself was opened electrically via a solenoid-actuated latch triggered by a button on the driver's door jamb. Over its three-year production, a total of 395 normally aspirated Taimars were built. The final body style for the M Series, an open roadster, arrived in 1978 as the TVR 3000S (marketed in some places as the "Convertible", and referred to at least once as the "Taimar Roadster".) Like the Taimar, the 3000S was mechanically identical to the 3000M; the body, however, had undergone significant changes. Only the nose of the car was the same as the previous coupes, as the windscreen, doors, and rear end had all been reworked. The windscreen and convertible top had been adapted from those used on the Jensen-Healey roadster, and the doors were cut down to better replicate a classic open-motoring experience. The redesign of the doors precluded the possibility of using wind-up windows, so sliding sidecurtains were instead fitted. These could be removed entirely and stowed in the trunk, which, for the first time on a TVR, was a separate compartment with its own lid. The trunk lid was operated electrically in a manner similar to the Taimar's hatch. The styling of the 3000S was revived in a somewhat modernized form later, with the 1987 introduction of the TVR S Series (although the S Series shared almost no components with the M Series cars.) One of the minor undocumented variations found on M Series cars is the presence of a map light built into the upper windscreen surround of the 3000S. It appears to have been included only on a very small number of cars built near the end of the production run. When production of the 3000S ended (with 258 cars built), it cost £8,730. Reportedly, 67 of these cars were in a left-hand drive configuration, and 49 were exported to North America. In 1977, aware that supplies of the US-emissions-certified Triumph 2.5L engine would soon be exhausted, TVR had contracted Californian company Olson Engineering, Inc. to design modifications to the Essex V6 such that it could be EPA-certified. They were successful in this regard, and Essex-engined M Series cars were imported the following year. An owner's handbook supplement for US Federal models indicates that the emissions control system used a catalytic converter, exhaust gas recirculation, and secondary air injection. In 1980, twenty-five 3000Ss were impounded by the United States government because a new US importer had declared them emissions-compliant without the Olson Engineering emissions kit actually having been fit. This was not discovered until the cars were moved to dealers, ready to be sold, and one customer reported the violation to the government. The cars were eventually re-exported to the UK, but the short-term financial impact of the twenty-five unsalable cars (worth £287,500 in total) was damaging to the development of the M Series replacement, the Tasmin. Specifications *Top speed - 121 mph (195 km/h) *Acceleration: :0-60 mph: 7.7 sec :30-50 mph in top: 6.6 sec :50-70 mph in top: 6.1 sec *Engine displacement - 2994cc (bore and stroke: 93.6 mm (3.7 in) x 72.4 mm (2.9 in)) *Engine type - Normally aspirated cast-iron V6 with pushrod-operated two-valve cast-iron heads *Compression ratio - 8.9:1 *Fueling - Twin-choke Weber carburetter *Peak power - 138 bhp (103 kW; 140 PS) @ 5000 rpm *Peak torque - 174 lb·ft (236 N·m) @ 3000 rpm *Transmission - 4-speed *Numbers built: :3000M: 654 :Taimar: 395 :3000S: 258 *Chassis numbers: :3000M: 2410FM through 4940FM :Taimar: 3838FM through 4966FM :3000S: 4286FM through 4968FM Turbos To further increase the performance of the 3000M, TVR contracted Ralph Broad's engine tuning company, Broadspeed, to develop a turbocharging system for the Essex engine. The resultant 3000M Turbo prototype was unveiled at the 1975 British International Motor Show at the Earls Court Exhibition Centre, and subsequently went into production. In lieu of fuel injection, a carburettor was run inside a pressurized box atop the engine, and the turbocharger itself was mounted low and forward in the engine compartment, requiring the exhaust manifolds to exit forward. The compression ratio was lowered to reduce the engine's internal stresses. The turbocharged cars were fitted with Koni dampers and wider tires than on the naturally aspirated model. Ultimately, TVR also produced small numbers of the Taimar Turbo and 3000S Turbo. Among all the Turbo cars, four were built with the "Special Equipment" (SE) specification, which included a leather interior, flared wheel arches, large Compomotive split-rim alloy wheels, and a limited-slip differential. Of these four cars, three were Taimar Turbo SEs and one was a 3000S Turbo SE. The single 3000S Turbo SE was used by Martin Lilley as his personal transport until he sold it on. The chassis numbers for the turbocharged cars were within the number ranges used by their normally aspirated counterparts. Specifications *Top speed - 140 mph (230 km/h) *Acceleration: :0-60 mph: 5.7 sec :30-50 mph in top: 7.1 sec :50-70 mph in top: 6.4 sec *Compression ratio - 8.0:1 *Fueling - Twin-choke Weber carburetter *Peak power - 230 bhp (172 kW; 233 PS) @ 5500 rpm *Peak torque - 273 lb·ft (370 N·m) @ 3500 rpm *Numbers built: :3000M Turbo: 20 :Taimar Turbo: 30 :3000S Turbo: 13 5000M In 1974, John Wadman (the president of the Canada-based import company TVR North America) began a project to replace the Triumph 2.5L engine in a silver 2500M with a Ford 302 cu in V8. Wadman handled the engineering of the conversion, which involved the use of different engine mounts, radiator, and springs. The Ford V8 was mated to a BorgWarner T-4 gearbox with a rear differential from the Chevrolet Corvette, and the resultant "5000M" was shown at the 1975 Toronto International Auto Show. Following the 1975 fire that damaged the TVR factory in Blackpool, TVR NA ordered and pre-paid six cars from the manufacturer. This gesture helped to secure future support from TVR for Wadman's V8 conversions: the factory eventually supplied five M Series coupes without engines or transmissions, specifically for the purpose of V8 installations. TVR NA also converted three cars that were originally equipped with the Ford Essex V6, but that arrived from the factory with cracks in the cylinder block. In 1978, the factory built a car (painted white with a brown stripe) that was designated "5000M"; this was also shipped to Canada for a V8 installation. Since 1980, six Taimars have been converted to the Ford V8 as well. Gallery 100_3778.JPG|1979 TVR M Series|link=http://www.flickr.com/photos/zacks_classic_cars/6696741959/ DSC02196S.JPG|1976 TVR 3000M DSC01396.JPG|1978 TVR M Series Category:TVR Category:Post-war